Proteins and especially immunoglobulins play an important role in today's medical portfolio. For human application every pharmaceutical substance has to meet distinct criteria. To ensure the safety of biopharmaceutical agents to humans nucleic acids, viruses, and host cell proteins, which would cause severe harm, have to be removed especially. To meet the regulatory specification one or more purification steps have to follow the manufacturing process. Among other, purity, throughput, and yield play an important role in determining an appropriate purification process.
Different methods are well established and widespread used for protein purification, such as affinity chromatography with microbial proteins (e.g. protein A or protein G affinity chromatography), ion exchange chromatography (e.g. cation exchange (carboxymethyl resins), anion exchange (amino ethyl resins) and mixed-mode exchange), thiophilic adsorption (e.g. with beta-mercaptoethanol and other SH ligands), hydrophobic interaction or aromatic adsorption chromatography (e.g. with phenyl-sepharose, aza-arenophilic resins, or m-aminophenylboronic acid), metal chelate affinity chromatography (e.g. with Ni(II)- and Cu(II)-affinity material), size exclusion chromatography, and electrophoretical methods (such as gel electrophoresis, capillary electrophoresis) (Vijayalakshmi, M. A., Appl. Biochem. Biotech. 75 (1998) 93-102).
Necina, R. et al., Biotechnol. Bioeng. 60 (1998) 689-698, reported the capture of human monoclonal antibodies directly from cell culture supernatants by ion exchange media exhibiting high charge density. In WO 89/05157 a method is reported for the purification of product immunoglobulins by directly subjecting the cell culture medium to a cation exchange treatment. A one-step purification of monoclonal IgG antibodies from mouse ascites is described by Danielsson, A., et al., J. Immun. Meth. 115 (1988), 79-88.
A combination of methods, i.e. a caprylic acid precipitation and ion exchange chromatography, was used by Raweerith, R. et al. (J. Immun. Meth. 282 (2003) 63-72), as means to fractionate pepsin-digested horse antivenom F(ab′)2 antibody. In WO 2003/102132 the combination of a non-affinity purification step and a high-performance tangential-flow filtration is reported for the purification of proteins. The combination of two affinity chromatography steps is reported in WO 92/19973.
Follman, D. K., and Fahrner, R. L., reported a factorial screening of antibody purification processes using three chromatography steps without protein A (J. Chrom. A 1024 (2004) 79-85). Mhatre, R. et al. (J. Chrom. A 707 (1995) 225-231), explored the purification of antibody Fab fragments by cation exchange chromatography and pH gradient elution.
WO 94/00561 reports human monoclonal anti-rhesus antibodies and cell lines producing the same. A method for purifying a polypeptide by ion exchange chromatography is reported in WO 2004/024866 in which a gradient wash is used to resolve a polypeptide of interest from one or more contaminants Schwarz, A. et al. (Laborpraxis 21 (1997) 62-66), report the purification of monoclonal antibodies with a CM-HyperD-column.
WO 2004/076485 reports a process for antibody purification by protein A and ion exchange chromatography. In EP 0 530 447 a process for purifying IgG monoclonal antibodies by a combination of three chromatographic steps is reported. The removal of protein A from antibody preparations is reported in U.S. Pat. No. 4,983,722.
WO 95/16037 reports the purification of anti-EGF-R/anti-CD3 bispecific monoclonal antibodies from hybrid hybridoma performed by protein A cation exchange chromatography. The separation of antibody monomers from its multimers by use of ion exchange chromatography is reported in EP 1 084 136. U.S. Pat. No. 5,429,746 relates to the application of hydrophobic interaction chromatography combination chromatography to the purification of antibody molecule proteins.